In an elevator system electromagnetic brakes are used as, inter alia, holding brakes of the hoisting machine and also as car brakes, which brake the movement of the elevator car by engaging with a vertical guide rail that is in the elevator hoistway.
The electromagnetic brake is opened by supplying current to the coil of the electromagnet of the brake and connected by disconnecting the current supply of the coil of the electromagnet of the brake.
Conventionally, relays have been used for the current supply/disconnection of the current supply, said relays being connected in series between a power source and the coil of the electromagnet of the brake.
Connecting a relay causes a noise, which might disturb the residents of a building. Relays are also large in size, owing to which their placement might be awkward, especially in elevator systems that have no machine room. As mechanical components, relays also wear rapidly and they might fail when, among other things, the contacts corrode or when they weld closed.